AW: [meteorite-list] Dho 025 lunar

From: Jörn Koblitz <koblitz_at_meteoritecentral.com>
Date: Mon Feb 21 09:32:03 2005
Message-ID: <E5E6112EA31FA24CB448E091C6883C052E5ECA_at_server2000.microfab.de>

Hello Bernd,

It is well possible that untrapped noble gases are the source of the vesicles. Dhofar 025 is a lunar regolith and so should contain large amounts of solar type noble gases (He-4, Ne-20) due to its long-time exposure to the solar wind. However, it contains only small amounts of solar-type gases, which is an indication of thermal metamorphism due to heavy shock. Other lunar regolith breccia like Y-983885 or QUE 93069 contain noble gases of up to 0.03 ccm/g material. Dhofar is depleted in such gases by two orders of magnitude. Instant outgassing of these gases (which were trapped in the silicates) by an impact event can explain the bubbles.

See also:
http://www.lpi.usra.edu/meetings/lpsc2001/pdf/1502.pdf

Cheers,
J?rn Koblitz / MetBase



> -----Urspr?ngliche Nachricht-----
> Von: bernd.pauli_at_paulinet.de [mailto:bernd.pauli@paulinet.de]
> Gesendet: Montag, 21. Februar 2005 13:31
> An: Meteorite-list_at_meteoritecentral.com
> Betreff: [meteorite-list] Dho 025 lunar
>
>
> > Anyone have any thoughts regarding the nature
> > of the vesicular clasts in the lunar Dho 025?
>
> > The clasts themselves are a couple of mm across
> > and contain numerous little bubbles / vesicles.
>
> > I was wondering where the vesicles come from,
> > what gases were trapped and so on.... !
>
> These melt pockets indicate intense shock after compaction by an
> impact event on the Moon. You are probably looking at melt glass
> (shock-melted plagioclase, anorthite and maybe silica glass) and
> the gases that were trapped are probably noble gases (not sure
> with regard to the noble gases).
>
> Best wishes,
>
> Bernd
>
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Received on Mon 21 Feb 2005 09:34:16 AM PST